One known method of displaying and playing back video and audio via a public switched telephone network (PSTN) line using electronic media, such as personal computers (PCs) and portable phones, is to use a communication function of such media (see, for example, http://www-6.ibm.com/jp/pc/desktop/index.shtml). Most desktop PCs include a display device, such as a cathode ray tube (CRT), and a central unit processor (CPU). Typically, the display device and CPU are housed in separate units. Most PCs are not easy to use. PCs including a main unit and a display device integrated in a single unit have problems of installation space, usability, etc. PCs, such as notebook PCs, have a space-saving design, but operation thereof is complex when used for multiple applications. Portable phones have a small display screen, making it difficult for a user to view the displayed content. The small display screen can provide only a limited amount of displayed information. The small screens of portable phones also have problems of poor usability and limited display area. Portable videophone devices have larger display areas than portable phones for viewing the expression of the other party. However, portable videophone devices are relatively large, and are frequently specific to one use.